Kim, D.H.; Park, K.C.; Kim, I.; Lee, J.L., and Lee, J., 2017. Calculation of rip current warning index by a vector rose diagram. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 109–113. Coconut Creek (Florida), ISSN 0749-0208.

Rip currents, which are sea tides that can carry swimmers into deep water beyond the breaking points, pose an immense security risk to beachgoers around the world. In Korea, rip current forecasting is divided into four warning levels: notice, watch, warning, and danger. However, the numerical results are represented by current vectors, and an additional process is necessary for converting these vectors into a predictive model. The primary goal of this study is to present a method that illustrates how to convert numerically simulated vectors into a rose diagram and how to divide this diagram into four warning levels for rip currents. The proposed method was validated by analyzing the correlation between warning indexes calculated from the present approach and those obtained from the NERiPs. The study was conducted at Haeundae Beach located in Busan, Korea. Different from the NERiPs, which is simply used to forecast the warning levels by the incident-wave conditions, this wave-induced currents model considers morphological effects.